Device for renewing an internal program of a facsimile machine

Abstract: A method and device of renewing an internal program of an apparatus communicatable with a central station operable to transmit a new apparatus control program. It is judged whether data received from the central station is a new program. Replacement is then executed of a previously stored program with the new program, if a new program is received. A previously stored internal program is automatically overwritten by a new program transmitted from the central station.

Description: BACKGROUND OF THE INVENTION This invention relates to a device for renewing a program stored in an internal program memory of a facsimile machine in communication with a central station. Japanese Unexamined Patent Publication No. 4-248754 discloses a facsimile machine in which a diagnostic program is loaded from external communication equipment into a writable memory of the machine. After executing a diagnostic test, the program is automatically abandoned or erased, regarding it as no longer necessary, to ensure effective use of the memory having a limited storage capacity. Also, Japanese Unexamined Patent Publication No. 4-323070 discloses a printing machine in which a debugging program is loaded from a read-only-memory (ROM) card or from a host computer when a bug is found in a control program of the printing machine. After debugging the control program, it is stored in an electrically erasable programmable ROM (EEPROM) so that there is no need to replace an internal ROM for correcting a program bug. In the above-mentioned facsimile machine, the diagnostic program or other add-on program for providing an extra function is temporarily written into a memory where facsimile image data is normally stored. It is therefore necessary to perform operations for data communication each time such a program is required. These operations are complicated and make it difficult to troubleshoot in a quick manner. In the above-mentioned printing machine, because the debugging program is loaded from a ROM card or from a host computer, it is necessary to turn off the machine and service personnel has to give debugging instructions each time a bug is found. Furthermore, since the program is specifically added for debugging purposes, it is written into extra addresses in the memory. This means that the memory must be provided with a spare capacity readily assigned to the debugging program and means for controlling individual tasks and address management. Moreover, it is necessary to prepare a dedicated ROM card for debugging or a host computer with a specially made debugging program and communication control software for controlling data transmission routine. The EP-A-0 569 178 discloses an apparatus and a method for downloading programs for a stored program controlled apparatus, in particular, for remote updating the entire set of programs of the apparatus including the "boot-up" segments. In accordance with this method downloading comprises two communication segments. In the first segment the essential portion of the new package of programs is downloaded to a chosen location in the local apparatus and a downloadable start address specification means is loaded with the appropriate new start address. Then, utilizing the recently downloaded set of essential programs, in the second segment the remainder of the new package of programs is downloaded. This method does not offer the possibility to judge whether the package of programs is new before downloading the first segment of the package. The JP-A-04 248 754 describes a means for a facsimile equipment, which is able to store a program received by other communication equipment into a write enable memory of the facsimile equipment and deletes the program after lapse of processing time. The means does not provide the possibility to first judge whether or not the program to be received is new before downloading the program. Therefore it is possible that an old program or a not required program is downloaded, while consuming time and memory. The JP-A-5 197 559 shows a system for downloading program data from a network controller to a network constitution device in a normal operation state. When new program data are transferred from a network controller in the state of operation by a program in an in-use EEPROM the new program data is stored in a stand-by EEPROM. Then the new program data is verified and at an initialization request from the network controller the device is started up by the program in the stand-by EEPROM. By use of this system the checking of the new program data also takes place after downloading the program. Such a method needs a lot of communication time, even if the program transferred from the network controller can not be used by the device, as for example the program is an old one. It is an object of the invention to provide a device for renewing a program stored in an internal program memory of a facsimile machine which saves memory of the facsimile machine and reduces the time needed for data transfer and data checking. This object is achieved by a device having the features disclosed in claim 1. Preferred embodiments are defined by the subclaims. The present invention is directed to a device for renewing a program stored in an internal program memory of an apparatus communicatable with a central station, the central station being operable to transmit data concerning a program and other contents, the device comprising: means for judging whether data transmitted from the central station is a new program; and means for replacing a previously stored program with the new program, if a new apparatus control program is transmitted. The device may be further provided with a data memory for storing the data transmitted from the central station. The judging means may be made to judge whether the data stored in the data memory is a new program, and the replacing means may be made to transfer the new program from the data memory to the internal program memory to replace the previously stored program with the new program. The device may be used for a facsimile machine. The judging means may be made to execute the judgment based on an NSS signal transmitted from the central station prior to transmission of data. The internal program memory may be operable to store an apparatus control program for controlling the apparatus and a renewal program for controlling the judging means and the replacing means. The central station is operable to transmit data concerning a new apparatus control program. The internal program memory may be constructed by a rewritable memory having a portion where the renewal program is written together with a write-inhibit code of inhibiting overwrite. The internal program memory may be constructed by a unwritable memory for storing the renewal program, and a rewritable memory for storing an apparatus control program. The internal program memory may be formed with two storage portions for storing an old apparatus control program and a new apparatus control program, respectively. The two storage portions may be made to store a transmitted new apparatus control program one after another. Further, the internal program memory may be provided with a unwritable memory for storing the renewal program. The two storage portions may be two rewritable memories respectively, the renewal program being written in a portion of one rewritable memory together with a write-inhibit code of inhibiting overwrite. In the case of the central station being operable to transmit data concerning a new renewal program in addition to a new apparatus program, the two storage portions may be constructed by two rewritable memories respectively, each having a portion for storing an apparatus control program and a renewal program. The two rewritable memories may be made to store a transmitted new apparatus control program and a transmitted new renewal program one after another. Further, the device may be provided with means for maintaining the apparatus powered on during the renewal operation. Accordingly, the discrimination is executed between a new program downloaded from a central station via a communication line and other incoming data, such as facsimile image data. If a new program is transmitted, a previously stored program is automatically overwritten by the new program. More specifically, the judgment is executed whether data received from a central station is a new program when a communication request signal is received from the central station. If it is a new program, the replacement is started up and the previously stored program is overwritten by the new program. As a result, the internal program of the apparatus can be renewed easily and surely. This arrangement also provides increased maintainability, eliminating the need for dispatching service personnel for fault diagnosis. Furthermore, a conventional ROM card or other dedicated storage media will no longer be required for renewing the internal program. If the apparatus is a facsimile machine, an NSS signal usable for setting a non-standard function included in signals exchanged between the central station and facsimile machine prior to data transmission is utilized to judge whether transmitted data is a new program. This eliminates the need for an additional signal for discriminating between image data transmission and program transmission. The arrangement in which the internal program memory is made of a single memory serves to achieve compact design and cost reduction of the apparatus. The arrangement in which the internal program memory is constructed by two memories and the replacement is alternately executed on the two memories each time a new apparatus control program is downloaded makes it possible to prevent the apparatus from becoming immediately unusable when a failure occurs in the apparatus, communication line or else during the program renewing since a previously stored apparatus control program still remains intact. In the case of data transmitted from the central station includes both an apparatus control program and a renewal program, renewal programs in the two memories are alternately renewed. Accordingly, it may be possible to renew both an apparatus control program and a renewal program simultaneously. Further, there is provided the means for keeping the apparatus powered on while the internal program is being renewed. Accordingly, the apparatus will not be powered off halfway during the program renewing process, and the renewing can be thus safely completed. Furthermore, if the central station registers and manages apparatus control programs for individual models of the apparatus, and whenever the apparatus control program of a specific model is upgraded to a higher version, establishes a communications link to individual apparatus of the relevant model and initiates downloading of the upgraded apparatus control program, the apparatus control program can be renewed promptly and surely, and increased reliability of the apparatus can be obtained with ease. These and other objects, features and advantages of the invention will become more apparent upon a reading of the following detailed description of the preferred embodiments with reference to the appended drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1A and 1B show a first circuit for renewing an apparatus control program embodying the invention. Fig. 1A being a block diagram depicting a circuit configuration for renewing the apparatus control program, and Fig. 1B being a diagram showing a memory map of a ROM circuit; Fig. 2 is a flowchart showing an apparatus control program renewal sequence of the first renewal circuit of Figs. 1A and 1B; Figs. 3A and 3B show a second circuit for renewing an apparatus control program embodying the invention, Fig. 3A being a block diagram depicting a circuit configuration for renewing the apparatus control program, and Fig. 3B being a diagram showing a memory map of a ROM circuit; Fig. 4 is a flowchart showing an apparatus control program renewal sequence of the second renewal circuit of Figs. 3A and 3B; Figs. 5A and 5B show a third circuit for renewing an apparatus control program embodying the invention, Fig. 5A being a block diagram depicting a circuit configuration for renewing the apparatus control program, and Fig. 5B being a diagram showing a memory map of a ROM circuit; Fig. 6 is a flowchart showing an apparatus control program renewal sequence of the third circuit of Figs. 5A and 5B; Fig. 7 is a flowchart showing a sequence for maintaining a communication apparatus powered on while it is connected to a central station, and Fig. 8 is a diagram showing a communication system between the communication apparatus and a central station. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Fig. 8 is a diagram showing a communication system between a facsimile machine and a central station. It should be noted that a facsimile machine is an example of communication apparatus which the present invention is embodied for. In Fig. 8, designated by the numeral 10 is a facsimile machine and designated by the numeral 9 is a central station. The central station 9 is provided with communication capability like the facsimile machine 10. The facsimile machine 10 comprises a central processing unit (CPU) 1 for controlling overall operation of the facsimile machine 10, a network control unit (NCU) 2 for controlling connection to and disconnection from a public communications network, a ROM circuit 3 including a rewritable EEPROM in which a program for executing individual tasks of facsimile functions is written, a RAM circuit 4 including a static RAM (SRAM) and a dynamic RAM (DRAM) as shown in Fig. 1 for temporarily storing received image data or original image data to be transmitted as well as a downloaded apparatus control program, an operating panel 5 including numeric keys for entering a facsimile number, keys for initiating transmission, setting transmit/receive formats and so on and a power switch 51, a display unit 6 including a liquid crystal display (LCD) for indicating operating status, a printing unit 7 for printing a received image, and a scanning unit 8 for reading and converting an original image to be transmitted into electrical image data. A detailed description will be given for the ROM circuit 3 and RAM circuit 4 later in this specification. As will be discussed later, the CPU 1 has a data discriminating function for judging whether received data is facsimile data sent from another facsimile machine or an apparatus control program sent from the central station 9. If the data is a downloaded apparatus control program, the CPU 1 writes it into the ROM circuit 3 to renew an existing apparatus control program. Also, the CPU 1 ensures that the facsimile machine 10 remains powered on in certain situations. For this purpose, the facsimile machine 10 has the following arrangement. The power switch 51 of the operating panel 5 is a common mechanical switch, such as a push-button switch having up and down positions or a rocker switch, either of which includes a moving element. The power switch 51 is associated with an electromagnetic lock mechanism 52 including a lock lever which is caused by a solenoid or a motor to protrude into or retract from where the moving element of the power switch 51 travels. With this arrangement, the power switch 51 is mechanically locked to an ON state while the solenoid (or motor) is activated even when an operator attempts to turn off the power switch 51. Alternatively, the power switch 51 may be associated with a relay which, when activated, supplies power to the facsimile machine 10 regardless of ON/OFF states of the power switch 51. In another alternative arrangement, the display unit 6 or a separate warning indicator (unillustrated) may be used instead of or in addition to the electromagnetic lock mechanism 52 to alert that the apparatus control program is being renewed. The printing unit 7 has a similar construction to an electrostatic copying machine comprising a photosensitive unit, a static charger, a developing unit, an image transfer unit, a fixing inn it and a light source such as a laser or a light emitting array to reproduce a received image signal or a common computer printer provided with a printer head. The scanning unit 8 comprises an array of image pickup elements for optically reading density variations on an original document and converting density information into an electric signal and a transport mechanism for feeding the original document to the scanning position. On the other hand, the central station 9 has its own NCU 91 for executing facsimile functions and a control unit 92 in which information on various models of facsimile machines and apparatus control programs for individual models are stored and managed in connection with individual facsimile numbers. The central station 9 is also provided with means for registering apparatus control programs. When an apparatus control program of a certain model has been upgraded, the new version of the apparatus control program is registered into an internal memory of the control unit 92 for later management. In such a case, the central station 9 produces a list of user terminals of the relevant model of which apparatus control program should be renewed. Then, the central station 9 calls individual user terminals and transmits the upgraded apparatus control program via a communications network. Given below is a brief description of a procedure for exchanging signals to be followed when the central station 9 (transmitter) calls the facsimile machine 10 (receiver) and renews its apparatus control program in accordance with the recommendations of the International Telegraph and Telephone Consultative Committee (CCITT). When a communications link has been established, the facsimile machine 10 working as a receiver transmits an NSF signal, a CSI signal and a DIS signal containing status information indicating whether the facsimile machine 10 is ready to record incoming data as well as its facsimile number, paper size, etc. to the central station 9 working as a transmitter. In response to these signals, the transmitter returns a TSI signal, an NSS signal and a TCF signal containing information on the transmitter such as its facsimile number and data transmission rate to the receiver. When the data transmission rate coincides between both sides, the receiver sends a CFR signal and then the transmitter starts transmission of data. If the transmitter is another facsimile machine, image data is sent page by page separated by end-of-page (EOP) signals. If the transmitter is the central station 9, it sends an apparatus control program. The NSS signal sent from the transmitter is usable for setting a non-standard function. Accordingly, this signal is preset to indicate that the transmitter is the central station 9 which will transmit an apparatus control program, or to include an identification signal which will make it possible to determine whether the transmitter is sending a control program or normal image data for facsimile if the transmitter can send both. Referring to Figs. 1A and 1B and 2, an apparatus control program renewal sequence according to a first embodiment of the invention is described. Fig. 1A is a block diagram depicting a circuit configuration for renewing the apparatus control program and Fig. 1B is a diagram showing a memory map of an EEPROM 31 contained in the ROM circuit 3. In Figs. 1A and 1B, circuit elements designated by like reference numerals as shown in Fig. 8 perform identical functions. The RAM circuit 4 of the first embodiment contains an SRAM and a DRAM. In this embodiment, the ROM circuit 3 contains only one rewritable EEPROM 31, of which addresses are divided into two areas: a memory area A at the beginning of addresses and a memory area B in succeeding addresses as shown in the memory map of Fig. 1B. The memory area A stores a program renew utility which is used when renewing the apparatus control program together with a write-inhibit code (e.g., "1") while the memory area B stores the apparatus control program. The CPU 1 and other circuits are connected together via a system bus SB so that instructions and data can be transmitted. It is to be noted here that the allocation of addresses of the EEPROM 31 is not limited to what is described above. The memory area A may be allocated in any appropriate address range instead of at the beginning of the memory map. Fig. 2 is a flowchart showing the apparatus control program renewal sequence of the first embodiment. First, it is judged whether the NSS signal from the central station 9 requests overwriting of the apparatus control program. If the received NSS signal requests program renewal (Step S2), the CPU 1 causes the RAM circuit 4 to once store a new apparatus control program that will be transmitted in succession into the SRAM or DRAM (Step S4). Upon receiving an EOP signal indicating the end of data transmission, the CPU 1 judges that the new apparatus control program has been completely received (Yes in Step S6). Then, the new apparatus control program temporarily stored in the RAM circuit 4 is transferred and written into the memory area B of the EEPROM 31 renewing the existing apparatus control program (Step S8). As seen above, the new apparatus control program downloaded from the central station is once stored in the RAM circuit 4 and upon completion of downloading the existing apparatus control program is renewed. This arrangement allows for sure reception and renewing of the apparatus control program. Referring now to Figs. 3A and 3B and 4, an apparatus control program renewal sequence according to a second embodiment of the invention is described. Fig. 3A is a block diagram depicting a circuit configuration for renewing the apparatus control program and Fig. 3B is a diagram showing a memory map of the ROM circuit 3. In this embodiment, the ROM circuit 3 comprises a ROM 32 for storing a renewal program and a rewritable EEPROM 33 in which the apparatus control program is registered. Fig. 4 is a flowchart showing an apparatus control program renewal sequence of the second embodiment. First, it is judged whether the NSS signal from the central station 9 requests overwriting of the apparatus control program. If the received NSS signal requests program renewal (Step S12), the CPU 1 causes the RAM circuit 4 to once store a new apparatus control program that will be transmitted in succession (Step S14). Upon receiving an EOP signal indicating the end of data transmission, the CPU 1 judges that the new apparatus control program has been completely received (Yes in Step S16). Then, the new apparatus control program temporarily stored in the RAM circuit 4 is transferred and written into the EEPROM 33 from the beginning of its addresses renewing the existing apparatus control program (Step S18). As seen above, the whole memory capacity of the EEPROM 33 is used for storing the apparatus control program. This approach allows for effective use of the memory capacity and facilitates management of addresses when renewing the apparatus control program. Referring next to Figs. 5A and 5B and 6, an apparatus control program renewal sequence according to a third embodiment of the invention is described. Fig. 5A is a block diagram depicting a circuit configuration for renewing the apparatus control program and Fig. 5B is a diagram showing a memory map of the ROM circuit 3. In this embodiment, the ROM circuit 3 is rewritable, preferably comprising a pair of EEPROM's, EEPROM (A) 34 and EEPROM (B) 35, having the same storage capacity. Each EEPROM has two address ranges, i.e., a memory area A at the beginning of addresses and a memory area B in succeeding addresses. The memory area A stores a program renew utility which is used when renewing the apparatus control program together with a write-inhibit code (e.g., "1") while the memory area B stores the apparatus control program. Each time the central station 9 requests overwriting of the apparatus control program, a new apparatus control program is written into EEPROM (A) 34 or EEPROM (B) 35, which is not currently active. Then, the CPU 1 switches the active EEPROM to use the upgraded apparatus control program. In one variation of this embodiment, the program renew utility may be stored in only one of the two EEPROM's whichever preselected. In another variation of this embodiment, the renewal program may be stored in a separate ROM as described in the second embodiment. In this case, there may be provided only one ROM or two ROM's for EEPROM (A) 34 and EEPROM (B) 35. When there is provided only one ROM, its entire storage capacity may be commonly used to apparatus control program renewal of EEPROM (A) 34 and EEPROM (B) 35 or divided into two address ranges to individually apparatus control program renewal of the two EEPROM's. Fig. 6 is a flowchart showing an apparatus control program renewal sequence of the third embodiment. First, it is judged whether the NSS signal from the central station 9 requests overwriting of the apparatus control program. If the received NSS signal requests program renewal (Step S22), the CPU 1 causes the RAM circuit 4 to once store a new apparatus control program that will be transmitted in succession (Step S24). Upon receiving an EOP signal indicating the end of data transmission, the CPU 1 judges that the new apparatus control program has been completely received (Yes in Step S26). Subsequently, if the currently used or active apparatus control program is the one stored in EEPROM (A) 34, the new apparatus control program temporarily stored in the RAM circuit 4 is transferred and written into the memory area B of currently unused or idle EEPROM (B) 35, renewing the apparatus control program existing therein (Step S28) as shown in the arrow X in Fig. 5B. Contrarily, if the currently used or active apparatus control program is the one stored in EEPROM (B) 35, the new apparatus control program is transferred and written into the memory area B of currently unused or idle EEPROM (A) 34, renewing the apparatus control program existing therein (Step S28) as shown in the arrow Y in Fig. 5B. Next, the CPU 1 switches between the active and idle EEPROM's so that the EEPROM containing the upgraded apparatus control program becomes active (Step S30) as shown in the arrow Z in Fig. 5B. An advantage of this third embodiment is as follows. The CPU 1 may be programmed to detect a system error status and continue to use the currently running apparatus control program if the apparatus control program renewal sequence is interrupted halfway due to any problem in the facsimile machine 10 or in a communications link. With this arrangement, it is possible to prevent the facsimile machine 10 from becoming immediately unusable in the event of failure in program renewal. In this case, the facsimile machine 10 may request the central station 9 to resend the apparatus control program using the NSS signal. In the third embodiment described above, there is made no provision for renewing the renewal program itself stored in the memory area A of each EEPROM. If, however, the central station 9 can transmit both a new renewal program and apparatus control program, the facsimile machine 10 may be constructed in such a manner that the renewal program stored in the memory area A of the currently active EEPROM would renew the old renewal program and control program stored respectively in the memory areas A and B of the currently idle EEPROM with new ones. In this case, the renewal program is not written together with the write-inhibit code. In any of the first to third embodiments described above, once the facsimile machine 10 is restarted after renewing the apparatus control program, it executes its tasks under the new apparatus control program. Fig. 7 is a flowchart showing a sequence for maintaining the facsimile machine 10 powered on while it is connected to the central station 9. First, it is judged whether the NSS signal from the central station 9 requests overwriting of the apparatus control program. If the received NSS signal requests program renewal (Step S42), the CPU 1 causes the RAM circuit 4 to once store a new apparatus control program that will be transmitted in succession (Step S44). When the new apparatus control program has fully been received with an EOP signal which indicates the end of data transmission (Yes in Step S46), the electromagnetic lock mechanism 52 is activated and locks the power switch 51 (Step S48). Then, with the power switch 51 locked in the ON position, the new apparatus control program temporarily stored in the RAM circuit 4 is transferred and written into the memory area B of the EEPROM 31 (in the case of the first embodiment) renewing the existing apparatus control program (Step S50). When the program renewal has been completed (Yes in Step S52), the power switch 51 is unlocked (Step S54). It is to be noted that this power lock sequence is applicable not only to the first embodiment but to the second and third embodiments. Also, the power lock sequence may be commenced from the point of time when renewing of the apparatus control program in the EEPROM is requested by the central station 9. According to the invention described above, either the apparatus control program or the program renew utility received from the central station 9 is once stored in the RAM circuit 4 before they are written into the EEPROM. In a modified form of the invention, either of them may be directly downloaded from the central station 9 into the EEPROM without passing through the RAM circuit 4 to achieve time savings in program renewal. Although the invention has been described with reference to several forms of preferred embodiments in a facsimile machine, it will be recognized by those skilled in the art that the invention is not limited to specific embodiments thereof but is applicable to a wide range of apparatus having communication capability that can transmit and receive information via a communication line and process or output the received information in a certain form.

Claims: A device for renewing a program stored in an internal program memory (3) of a facsimile machine in communication with a central station (9), the central station (9) being operable to transmit data concerning a program and other contents, the device comprising: judging means (1) for judging whether data transmitted from the central station is a new program; replacing means (1) for replacing a previously stored program with the new program, if a new control program is transmitted; and, means (52) for maintaining if desired the apparatus powered on during the renewal operation; characterized in that the judging means (1) is operable to execute the judgement based on an Non-Standard function Signal, NSS signal, transmitted from the central station (9) prior to the transmission of data. A renewing device as defined in claim 1 further comprising a data memory (4) for storing the data transmitted from the central station (9), characterized in that the judging means (1) is operable to judge whether the data stored in the data memory (4) is a new program; and the replacing means (1) is operable to transfer the new program from the data memory (4) to the internal program memory (3) to replace the previously stored program with the new program. A renewing device as defined in claim 1, characterized in that the internal program memory (3) is operable to store an apparatus control program for controlling the apparatus and a renewal program for controlling the judging means (1) and the replacing means (1); and the central station (9) is operable to transmit data concerning a new apparatus control program. A renewing device as defined in claim 3, characterized in that the internal program memory (3) is a rewritable memory, and the rewritable memory has a portion (33) where the renewal program is written together with a write-inhibit code of inhibiting overwrite. A renewing device as defined in claim 3, characterized in that the internal program memory (3) includes: a read-only memory (32) for storing the renewal program; and/or a rewritable memory (33) for storing an apparatus control program. A renewing device as defied in claim 3 or 5, characterized in that the internal program memory (3) has two storage portions (34, 35) for storing a currently running apparatus control program and a new apparatus control program, respectively. A renewing device as defined in claim 6, characterized in that the two storage portions (34, 35) are operable to store a transmitted new apparatus control program one after another. A renewing device as defined in claim 7, characterized in that the two storage portions (34, 35) include two rewritable memories (34, 35) respectively, and the renewal program is written in a portion of one rewritable memory (34; 35) together with a write-inhibit code of inhibiting overwrite. A renewing device as defined in claim 6, characterized in that the central station (9) is operable to transmit data concerning a new renewal program in addition to a new apparatus control program; and the two storage portions (34, 35) include two rewritable memories (34, 35) respectively, each having a portion for storing an apparatus control program and a renewal program. A renewing device as defined in claim 9, characterized in that the two rewritable memories (34, 35) are operable to store a transmitted new apparatus control program and a transmitted new renewal program one after another.

Inventors: INOUE MASAHIRO, NAGATA KATSUMI, NAKAMURA HIROAKI, SHIBATA TETSUYA, INOUE, MASAHIRO, NAGATA, KATSUMI, NAKAMURA, HIROAKI, SHIBATA, TETSUYA, INOUE, MASAHIRO, C/O MITA INDUSTRIAL CO., LTD., NAGATA, KATSUMI, C/O MITA INDUSTRIAL CO., LTD., NAKAMURA, HIROAKI, C/O MITA INDUSTRIAL CO., LTD., SHIBATA, TETSUYA, C/O MITA INDUSTRIAL CO., LTD.
Applicants: MITA INDUSTRIAL CO LTD, MITA INDUSTRIAL CO. LTD.
Application year: 1994
Main classification: H04N1
IPC codes: H04N1, G06F9, G06F13